High-efficiency and long-lifetime deep-blue organic light-emitting diode with a maximum external quantum efficiency of 20.6% and CIEy of 0.04

Abstract

We synthesized a diphenylamine modified pyrene derivative, 4,9-diisopropyl-N,N,N′,N′-tetrakis-(4-methyl-biphenyl-3-yl)-pyrene-1,6-diamine (DITBDAP), and successfully applied it to deep-blue organic light-emitting diodes (OLEDs). The DITBDAP-based top-emitting OLED was featured by a high maximum external quantum efficiency (EQEmax) of 20.6%, an extremely low CIEy (Commission International de L'Eclairage coordinates) of 0.04, a narrow full-width at half maximum of 16 nm, and a long lifetime of 250 h. We chose 6,12-bis[6-trimethylphenyl)]amino5-trimethylphenyl)]amino] pyrene (Bmpac) as the comparison material due to its similar structure to DITBDAP. The DITBDAP-based bottom-emitting OLED showed a better performance compared to that of the Bmpac-based OLED, with the T95 lifetime (time to 95% of the initial luminance of 3000 cd m−2) of 250 h, which was more than twice that of the Bmpac-based OLED. In addition, the efficiency roll-off was extremely low at high brightness, which were 1% at 1100 cd m−2 and 5% at 3200 cd m−2. The synthesized DITBDAP has realized highly efficient and long-lifetime deep-blue OLEDs with the EQE up to 20.6% and CIEy as low as 0.04.